Discogenic Pain

Among the many causes of back pain, is a disorder that back specialists refer to as Discogenic Back Pain. This disease is usually seen in the active adult 30-40 years of age but could be seen in other age groups as well. The disease is manifests with a range of intensity. The major complaint is back pain without radiation to the legs. The pain is concentrated in the lower back but may also be felt in the buttocks and the upper thighs. This may be combined with stiffness, cramping, and aching. There is usually low tolerance to prolonged and continuous sitting or standing. Many patients also experience increased discomfort with driving or flying. Any activity that places stress on the disc may initiate the perception of pain.

The normal disc (usually seen in very young people) has a high concentration of water. As we age, our bodies slowly loose water, and the consequence of the decreased water content translates to decreased ability of the disc to resists the normally applied forces. With the decreased ability to resist these forces, more motion is seen across the disc which stimulates the very small nerves in the outer covering of the disc. These small nerves are usually the cause of back pain in this disease. Many times we see patients complaining of pain in the buttocks area. The sensation of pain in that area is usually a referred type of a pain. In other words, even though the pain is not generated in the buttocks area, there is a perception that the pain is coming from that area.

Discogenic lower back pain is a very difficult disease process encountered by spine specialists. It usually inflicts relatively young patients and dramatically affects their life style. The pain has a range from being disabling to just a discomfort. The usual diagnostic studies are performed and they begin with a plain X-ray. The X-ray could be completely normal or show severe degeneration of the specific area. An MRI is the second line of testing which will allow us to visualize the disc more directly. The amount of hydration (water content) is a clue to the “health” of the disc. The hydrated and healthy disc will appear more white on the MRI, as opposed to the degenerated disc which has a dark color on the MRI. The MRI to the right shows a normal subject with well hydrated and tall discs which appear white in color on the MRI. In contrast, the MRI to the left has discs that are dark (labeled in red). Still, a dark disc on an MRI does not necessarily mean a painful lumbar disc. To further delineate the source of back pain, some spine specialists will suggest a test called Discogram. This test attempts to reproduce the usual (typical) pain experienced by the patient by injecting the suspected disc with a fluid to increase disc pressures. If the usual pain is reproduced upon injection of the disc, it is assumed with a higher degree of confidence that the pain is generated by that specific disc.

Most physicians approach this disease with conservative treatment options. The most common therapy used is physical therapy. Specific exercises are available in rehabilitating the patient with discogenic low back pain. The theory behind these therapies is the stretching of tight soft tissue structures and strengthening of back musculature to provide more support to the bony structures. Postural exercises are prescribed as well to reduce the stress on the structures of the spine. With these treatment options we hope to decrease the perceived pain, increase strength and endurance, and prevent recurrence. If these therapies eventually fail to improve symptoms, the physician and patient may choose to try injection of anti-inflammatory medications like steroid into the spinal canal in order to reduce inflammation and hopefully the associated pain. The Epidural Steroid injection may provide pain relief to many patients but their long term benefit has not been proven in the scientific literature. Other treatment options are also available but may be less reliable in preventing recurrence. There is a long list of other options available and these may include acupuncture, hydro-therapy, bio-feedback, chiropractic, heat/cold therapy, acupressure, etc. Almost all of these therapies will provide immediate symptomatic relief of pain but their long lasting effects have not been proven.

Most patients benefit from medications that suppress inflammation. These medications include the Non-Steroidal Anti-Inflammatory Drugs. The most basic example of these medications is Aspirin. Throughout the years, more sophisticated drugs been developed to produce more effective actions with less side effects (Celebrex, Vioxx, Mobic). Common to all of these medications is the risk for stomach ulcers. The newer drugs claim to have lower side effects with less interaction with other drugs. There is a long list of choices available when choosing a medication and certain drugs may be more effective on one patient compared to another. There is also a small risk to the kidney and liver while on these medications. However, the risks and benefits of these drugs should be considered, and most patients elect to take these medications since the pain of this disease may be very disabling.

Most patients will benefit from conservative modalities as mentioned above. These modalities are performed to avoid more aggressive and invasive procedures. A new procedure was recently introduced to spine surgeons and is called IDET (Intra-Discal Electro-Thermal Therapy). Many spine specialists have doubts regarding the indications and outcome of this procedure. A few reports were recently published indicating that about half the people undergoing this procedure will have reduction of their pain in 50%. About quarter of the people will have substantial relief of pain. And a quarter of the people will have no relief. A very small group of patients may have worsening of the symptoms. The procedure is relatively simple and involves the placement of a needle into the disc, followed by heating of the disc to a specific temperature. It is theorized that the nerves causing the pain are destroyed and the tear in the outer covering of the disc is sealed. Patients are brought to the surgery center and are released the same day. Since this procedure may irritate the disc, the pain may intensify for one or two days. The benefits of this procedure can be seen up to 6 months later. For that reason, it is important to wait until the full benefit of this procedure is realized. However, this procedure cannot be performed any all patients. The disc must be tall enough to allow insertion of the catheter. In severely degenerated discs, the bony ends of the vertebrae may be touching each other. This will not allow the insertion of the probe and patients inflicted with this disorder may benefit from surgical correction rather than the IDET procedure. The IDET procedure is favored by some surgeons since it does not prevent the patient from having surgical correction at a later date. For this reason, patients who are candidates for surgical disc removal may choose to try this procedure first. If this procedure succeeds, then the operation is avoided. If the IDET is not successful, then the original plan of surgery is followed. By this plan of treatment, it is hoped that some patients may avoid having surgery on their spine.

A small group of patients will not benefit from the above treatment plans. Indeed, this is a small group of patients since most benefit from conservative modalities. These patients will be offered a surgical procedure to remove the offending disc, followed by fusion of that specific level/s only. This can be performed using several different procedures. There is still some controversy as to the best way of achieving fusion of the level from which the disc was removed. Several basic concepts are mentioned here to better explain the theories. The more stable the area to be fused, the higher the likelihood for success. The procedure could be performed endoscopically or in the traditional open approach. And the surgical approach to the spine is yet another broad subject. The first issue is the use of metallic implants (instrumentation) to achieve stability. It is without doubt that instrumentation (metallic implants to hold the position of fusion until the body forms new bone and heals) provides stability and improves fusion rates. We also know that some patients will not fuse the proposed level and may continue to have pain from the non-union in that area. For that reason, we choose to instrument most of our patients. We believe that we can achieve superior results, with higher fusion rates, and higher patient satisfaction with instrumentation. In regards to the subject of endoscopic fusion, many reports are now available to show disastrous complications from laparoscopic/endoscopic front approaches to the spine. We do believe in minimally invasive procedures, however, in this case the chance for sever vascular bleeding, and damage to the internal organs are higher than the small incision required to perform the operation. The risks of laparoscopic/endoscopic procedure in this diagnosis are higher than the benefits. In regards to the approaches to the spine, we choose to approach the spine from the front as well as the back. From the front approach to the spine we are able to remove the disc in its entirety safely and efficiently, followed by placement of bone graft to allow optimal bone regeneration and healing. After completion of the procedure from the front, we proceed to approach the spine from the back. Nerves can be decompressed from the back if needed, and then that section fused with instrumentation. This combined approach is referred to “Front & Back Surgery”. In many reports it is indicated that this approach achieves that highest level of stability with the highest chance of fusion as compared with “front only” approaches. Still yet another approach is the “back only” approach which is called PLIF (Posterior Lumbar Interbody Fusion) procedure. With this procedure the spine is approached from the back. Enough bone is removed to visualize the neural elements. At that time they are pushed gently to the side and the disc is removed. Bone graft is inserted in that area to achieve fusion. Metallic implants are inserted to achieve rigidity for enhanced fusion rates. The theoretical advantage of this procedure is the avoidance of a second scar in front of the spine and the entire operation is performed from the same back incision. However, it is technically more difficult and risky. There is a higher complication rate with this procedure, and visualization is hindered. Furthermore, there is much traction on the nerves in order to enter the disc space which can place the neural elements in higher danger during this procedure. For these reasons, we prefer the “front & back surgery” to remove the disc and achieve a higher chance for fusion. In previous years this procedure was performed as a “Front only” procedure (also referred to as ALIF or Anterior Lumbar Interbody Fusion). The spine was approached from the front, the disc removed, and the level was fused from the front only without the additional surgical procedure from the back. The needed rigidity is harder to obtain with a “front only” surgery and fusion rates were lower with lower rates of pain relief. There are text books written regarding the above subjects and much research is still needed to conclude definite answers. For now, your spine surgeon can best use his knowledge and experience to arrive at an answer that best suited for the your needs. If you have questions, call today to make an appointment and discuss your special needs.